Polyfluoroalkyl allyl compound and method for producing the same

ABSTRACT

A carboxylic acid allyl adduct of the general formula:
 
CF 3 (CF 2 ) n (CH 2 CF 2 ) a (CF 2 CF 2 ) b CH 2 CHICH 2 OCOR′  [II]
         wherein n is an integer of 0 to 5, a is 1 or 2, and b is an integer of 0 to 3, and R′ is a C 1 -C 3  alkyl group.

RELATED APPLICATION

This application is a divisional application of U.S. Non-Provisionalpatent application Ser. No. 15/512,446, filed Mar. 17, 2017 which inturn is a 35 U.S.C. § 371 national phase filing of International PatentApplication No. PCT/JP2015/076700, filed Sep. 18, 2015, which claimspriority under 35 U.S.C. § 119 to Japanese Patent Application No.2014-200045, filed Sep. 30, 2014. Priority of this application isclaimed under 35 U.S.C. § 120 to U.S. patent application Ser. No.15/512,446 and International Patent Application No. PCT/JP2015/076700and further claimed under 35 U.S.C. § 119 to Japanese Patent ApplicationNo. 2014-200045, the entire disclosure of each being hereby expresslyincorporated by reference.

TECHNICAL FIELD

The present invention relates to a polyfluoroalkyl allyl compound and amethod for producing the same. More particularly, the present inventionrelates to a polyfluoroalkyl allyl compound that is used as a syntheticintermediate for a fluorine-containing alkylsilane compound having ahigh water contact angle, and a method for producing the same.

BACKGROUND ART

In general, compounds having a perfluoroalkyl group as a structural unitare known to improve surface modifying properties, water- andoil-repellency, mold releasability, antifouling properties, levelingproperties, etc., of various substrates, such as fiber, metal, glass,rubber, and resin, by chemical treatment of the surface of eachsubstrate.

Among such compounds, telomer compounds containing a perfluoroalkylgroup having 8 to 12 carbon atoms are most likely to exhibit the aboveproperties. Telomer compounds having 8 carbon atoms are preferably used.

However, it has been recently reported that perfluorooctanoic acidhaving 8 carbon atoms or perfluorocarboxylic acids having more than 8carbon atoms have adverse effect on the environment, because they havelow degradability and high bioaccumulation potential, and there issuspicion of biological toxicity. Among these compounds, thosecontaining a perfluoroalkyl group having more than 8 carbon atoms aresuggested to be possibly converted to perfluorooctanoic acid orperfluorocarboxylic acids having more than 8 carbon atoms bybiodegradation or chemical degradation in the environment, and there isconcern that it will become difficult to produce and use those compoundsfor the future. However, compounds containing a perfluoroalkyl grouphaving 6 or less carbon atoms are said to have low bioaccumulationpotential.

Fluorine-containing alkylsilane compounds containing a perfluoroalkylgroup having 6 or less carbon atoms and having a high water contactangle are also known.

Patent Document 1 discloses a method for obtaining a fluorine-containingalkylsilane compound having terminal —CH₂CH₂Si(R¹)_(3-n)X_(n) byreducing, with a reducing agent, a compound obtained by an additionreaction of R^(F)(CH₂CH₂)_(a)(CH₂CF₂)_(b)(CF₂CF₂)_(c)I withCH₂═CHSi(R¹)_(3-n)X_(n).

In this method, however, iodine is desorbed in the final step, and thereis thus a concern about coloring of the target compound with iodine. Inaddition, there is a problem that hydrogenated tributyltin and the likethat have a high environmental load are used in the deiodinationreaction. Moreover, it is described that a compound having a CH₂ groupbetween a CF₂ group and a CF₂ group is weak under basic conditions,which means that the reaction conditions (synthetic route) are limited.

Patent Document 2 indicates that silane coupling agents having abiphenyl alkyl group Rf(C₆H₄—C₆H₄)CH₂CH₂CH₂Si(OCH)₃ are compounds havingexcellent heat resistance, durability, mold releasability, andantifouling properties, so that the contact angle of surfaces modifiedby these compounds are not reduced even after exposure to an atmosphereat a high temperature of 350° C. or more.

However, these compounds are solids at ordinary temperature because ofthe biphenyl skeleton in their molecules, and may be thus difficult tohandle. Further, organic lithium, such as n-butyllithium, is used as areaction reagent. This is a highly reactive and water-prohibitingregent. It is thus necessary to slowly drop such a reagent under lowtemperature conditions, since, for example, control of the reaction heatduring the reaction becomes necessary. Thus, handling properties arepoor, and the process used therein is not suitable for large-scaleproduction.

A fluorine-containing alkylsilane compound having a bifunctionalorganosiloxane group is described in Patent Document 3.

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: JP-A-2014-40373

Patent Document 2: WO 2008/108438 A1

Patent Document 3: JP-A-2009-137842

Patent Document 4: JP-B-5292826

OUTLINE OF THE INVENTION Problem to be Solved by the Invention

An object of the present invention is to provide a polyfluoroalkyl allylcompound used as a synthetic intermediate for a fluorine-containingalkylsilane compound that can remove free iodine derived from the rawmaterial compound, before a hydrosilylation reaction is performed,without using a metal reagent having a high environmental impact, andthat has excellent handling properties; and to also provide a method forproducing the same.

Means for Solving the Problem

The present invention provides a polyfluoroalkyl allyl compoundrepresented by the general formula:CF₃(CF₂)_(n)(CH₂CF₂)_(a)(CF₂CF₂)_(b)CH₂CH═CH₂  [I]wherein n is an integer of 0 to 5, a is 1 or 2, and b is an integer of 0to 3.

The polyfluoroalkyl allyl compound is produced by reacting a carboxylicacid allyl adduct represented by the general formula:CF₃(CF₂)_(n)(CH₂CF₂)_(a)(CF₂CF₂)_(b)CH₂CHICH₂OCOR′  [II]wherein n, a, and b are as defined above, and R′ is a C₁-C₃ alkyl group,with a transition metal.

Effect of the Invention

The polyfluoroalkyl allyl compound of the present invention is used as areaction raw material (synthetic intermediate), and afluorine-containing alkylsilane compound having a terminal—SiR_(3-d)X_(d) group can be produced by reacting it with alkoxysilaneusing a transition metal catalyst, or by reacting it with chlorosilane,followed by a reaction with lower alcohol or metal alkenyl. In thisreaction, free iodine derived from the raw material compound can beremoved before a hydrosilylation reaction is performed, and handlingproperties are excellent. Moreover, a fluorine-containing alkylsilanecompound to which a suitable hydrosilylating agent is added can bechemically bonded to the surface of various substrates, therebyimparting water- and oil-repellency, antifouling properties, etc.,thereto.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

The polyfluoroalkyl allyl compound of the present invention and thefluorine-containing alkylsilane compound produced by using thepolyfluoroalkyl allyl compound of the present invention as a reactionraw material (synthetic intermediate) are produced through the followingseries of steps:

(1) A compound:CF₃(CF₂)_(n)(CH₂CF₂)_(a)(CF₂CF₂)_(b)I  [III]is reacted with carboxylic acid allyl ester R′COOCH₂CH═CH₂.(2) The resulting product:CF₃(CF₂)_(n)(CH₂CF₂)_(a)(CF₂CF₂)_(b)CH₂CHICH₂OCOR′  [II]is reacted with a transition metal.(3) The resulting product:CF₃(CF₂)_(n)(CH₂CF₂)_(a)(CF₂CF₂)_(b)CH₂CH═CH₂  [I]is reacted with alkoxysilane,orreacted with chlorosilane, followed by a reaction with C₁-C₃ loweralcohol or metal alkenyl,thereby obtaining the following compound:CF₃(CF₂)_(n)(CH₂CF₂)_(a)(CF₂CF₂)_(b)(CH₂)₃SiR_(3-d)X_(d)  [IV].Examples of C₁-C₃ lower alcohol usable herein include fluorine-freealcohols, such as methanol, ethanol, propanol, and isopropanol; andfluorine-containing alcohols, such as trifluoroethanol,tetrafluoropropanol, and hexafluoroisopropanol. Moreover, examples ofmetal alkenyl include allyl magnesium chloride, allyl magnesium bromide,and the like.

The polyfluoroalkyl iodide [III] used as a raw material compound in step(1) above is a known compound, and disclosed, for example, in PatentDocument 4.

Specific examples of the polyfluoroalkyl iodide used include thefollowing compounds:

CF₃(CF₂)(CH₂CF₂)I

CF₃(CF₂)(CH₂CF₂)₂I

CF₃(CF₂)₂(CH₂CF₂)I

CF₃(CF₂)₂(CH₂CF₂)₂I

CF₃(CF₂)₃(CH₂CF₂)I

CF₃(CF₂)₃(CH₂CF₂)₂I

CF₃(CF₂)(CH₂CF₂)(CF₂CF₂)I

CF₃(CF₂)(CH₂CF₂)(CF₂CF₂)₂I

CF₃(CF₂)₂(CH₂CF₂)(CF₂CF₂)I

CF₃(CF₂)₂(CH₂CF₂)(CF₂CF₂)₂I

CF₃(CF₂)₃(CH₂CF₂)₂(CF₂CF₂)I

CF₃(CF₂)₃(CH₂CF₂)₂(CF₂CF₂)₂I

As a slightly excess mole number of carboxylic acid allyl esterR′COOCH₂CH═CH₂ to be reacted with such a polyfluoroalkyl iodide,compounds, in which R′ has a C₁-C₃ alkyl group, preferably allyl acetateare used. This reaction is performed as a radical addition reaction at atemperature of about 70 to 120° C. in the presence of a radicalinitiator in an amount of about 0.001 to 1.0 mol % based on thepolyfluoroalkyl iodide. Examples of the radical initiator includeperoxydicarbonates, such as di-n-propyl peroxydicarbonate, diisopropylperoxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate,di(2-ethoxyethyl) peroxydicarbonate, di(2-ethoxyhexyl)peroxydicarbonate, di(3-methoxybutyl) peroxydicarbonate, anddi-sec-butyl peroxydicarbonate.

The resulting carboxylic acid allyl adduct [II] is reacted with atransition metal, for example, a simple metal such as Zn, Mg, Mn, Cu ora reagent thereof, preferably simple Zn, as the reduction of iodine andolefination reaction. The carboxylic acid allyl adduct and thetransition metal are each used together with a solvent, such as methanoland ethanol. Moreover, the transition metal is used in a slightly excessmolar ratio based on the carboxylic acid allyl adduct.

The resulting polyfluoroalkyl allyl compound [I]:CF₃(CF₂)_(n)(CH₂CF₂)_(a)(CF₂CF₂)_(b)CH₂CH═CH₂is reacted with an alkoxysilane to thereby yield:CF₃(CF₂)_(n)(CH₂CF₂)_(a)(CF₂CF₂)_(b)(CH₂)₃SiR_(3-d)X_(d)

Examples of alkoxysilane include trimethoxysilane, triethoxysilane,tripropoxysilane, and the like, having a C₁-C₃ lower alkoxy group. Thealkoxysilane is used in slightly excess molar ratio based on theterminal allyl compound.

The reaction is performed at a reaction temperature of about 25 to 100°C. in the presence of a transition metal catalyst. Examples oftransition metal catalysts, preferably Pt-based or Rh-based catalysts,include chloroplatinic acid H₂PtCl₁₆.6H₂O, Karstedt's catalystPt·CH₂═CHSiMe₂OMe₂OSiCH═CH₂, Wilkinson's catalysts RhCl[P(C₆H₅)₃]₃,RhH[P(C₆H₅)₃]₄, and the like. The catalyst is used in an amount of about0.001 to 10 mol % based on the polyfluoroalkyl allyl compound.

The polyfluoroalkyl allyl compound [I] can also be reacted with slightlyexcess molar ratio of chlorosilane, followed by a reaction with C₁-C₃lower alcohol or metal alkenyl, thereby obtaining the target compound.The reaction with chlorosilane is performed using a transition metalcatalyst as mentioned above at a ratio of about 0.001 to 10 mol % basedon the polyfluoroalkyl allyl compound at a reaction temperature of about25 to 100° C., and after imparting —SiCl₃ to a terminal group, theresultant is reacted with a C₁-C₃ lower alcohol or metal alkenyl at areaction temperature of about 25 to 120° C. In this case, a loweralcohol or metal alkenyl can be reacted in an amount of less than 3equivalents based on the terminal —SiCl₃ group, thereby allowing halogento remain in the terminal group.

The obtained fluorine-containing alkylsilane compound has a high watercontact angle, which indicates a low surface free energy, and thereforeindicates high mold releasability, and high antifouling properties.

EXAMPLES

The following describes the present invention with reference toExamples.

Example 1

A 1000-ml three-necked flask was equipped with a dropping funnel and aDimroth condenser in the presence of inert nitrogen gas. 400 g (0.66mol) of polyfluoroalkyl iodide CF₃(CF₂)₃(CH₂CF₂)(CF₂CF₂)₂I was chargedin the three-necked flask, while 74.0 ml (0.69 mol) of allyl acetateCH₂═CHCH₂OCOCH₃ and 2.61 g (6.5 mmol) of a radical initiator P-16[di(tert-butylcyclohexyl) peroxydicarbonate] were placed in the droppingfunnel, respectively, and the content of the three-necked flask wasstirred. When the temperature reached 90° C., droppings from thedropping funnel was started to initiate reaction. Heat generation becameweak in the latter half of the reaction; therefore, 0.09 g of P-16 wasadded to allow the reaction to continue.

Two hours later after completion of the heat generation, the temperaturewas cooled to room temperature. The reaction mixture was analyzed by NMRand gas chromatography to confirm the structure and conversion of thereaction product. The conversion of the target product was 87%.Unreacted raw material compounds were removed by vacuum distillation,thereby obtaining 391 g (95% GC, yield: 84%) of light yellow solid allylacetate adduct.

CF₃CF₂CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂CH₂CHICH₂OCOCH₃

¹⁹F-NMR (d-acetone, 282.65 Hz):

−80.2:CF₃ CF₂CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂CH₂—

−110.3:CF₃CF₂CF₂CF₂ CH₂CF₂ CF₂CF₂CF₂CF₂CH₂—

−112.2:CF₃CF₂CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂ CH₂—

−120.2:CF₃CF₂CF₂CF₂CH₂CF₂CF₂ CF₂CF₂CF₂CH₂—

−121.9:CF₃CF₂CF₂ CF₂CH₂CF₂CF₂CF₂CF₂ CF₂CH₂—

−122.5:CF₃CF₂CF₂ CF₂CH₂CF₂CF₂CF₂CF₂ CF₂CH₂—

−124.9:CF₃CF₂ CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂CH₂—

Example 2

A 500-ml three-necked flask was equipped with a dropping funnel and aDimroth condenser in the presence of inert nitrogen gas. 180 ml ofmethanol and 20.1 g (0.33 mol) of Zn were placed in the flask, while 200g (0.28 mol) of the allyl acetate adduct obtained in Example 1 and 20 mlof methanol were placed in the dropping funnel, respectively, and thecontent of the three-necked flask was stirred. When reflux started tooccur, droppings from the dropping funnel was started to initiatereaction. After dropping, the resulting mixture was stirred for 2 hours,and then cooled to room temperature to stop the reaction.

Since the phase separation of the reaction mixture was unclear, anattempt was made to cause liquid separation by distilling off themethanol; however, an emulsion was formed. Accordingly, the precipitatewas filtered, followed by liquid separation again and drying, therebyobtaining 123.7 g (92% GC, yield: 77%) of the target compound, i.e., atransparent liquid terminal allyl compound. In this reaction, it wasconfirmed that the reaction proceeded with good reproducibility,irrespective of the purity of the starting material. Next, vacuumdistillation was performed to increase the purity to 97% GC.

CF₃CF₂CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂CH₂CH═CH₂

¹H-NMR (d-acetone, 300.4 Hz):

-   -   δ5.9-5.7:—CF₂CH₂CH═CH₂(m)        -   5.4:—CF₂CH₂CH═CH₂ (m)        -   3.6:—CF₂CH₂ CF₂-(quin)        -   3.0:—CF₂CH₂ CH═CH₂(dt)

¹⁹F-NMR (d-acetone, 282.65 Hz):

-   -   −80.2:CF₃ CF₂CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂CH₂—    -   −110.2:CF₃CF₂CF₂CF₂ CH₂CF₂ CF₂CF₂CF₂CF₂CH₂—    -   −111.9:CF₃CF₂CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂ CH₂—    -   −120.3:CF₃CF₂CF₂CF₂CH₂CF₂ CF₂CF₂CF₂CF₂CH₂—    -   −121.9:CF₃CF₂CF₂CF₂CH₂CF₂CF₂CF₂ CF₂CF₂CH₂—    -   −122.1:CF₃CF₂CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂CH₂—    -   −122.5:CF₃CF₂CF₂CF₂CH₂CF₂CF₂CF₂CF₂ CF₂CH₂—    -   −124.9:CF₃CF₂ CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂CH₂—

Reference Example 1

A 100-ml three-necked flask was equipped with a septum and a Dimrothcondenser in the presence of inert nitrogen gas. 20.0 g (0.04 mol) ofthe terminal allyl compound obtained in Example 2 and 5.8 ml (0.05 mol)of triethoxysilane were placed in the three-necked flask. The content ofthe three-necked flask was stirred, and the temperature was increased to80° C. After the temperature increase, 20 mg (0.05 mol % based on theterminal allyl compound) of chloroplatinic acid H₂PtCl₁₆.6H₂O was addedto initiate reaction. After stirring for the whole day and night, thereaction mixture was cooled to room temperature to stop the reaction.

The reaction mixture was subjected to vacuum distillation, therebyobtaining 10.7 g (yield: 42%) of the target compound, i.e., atransparent liquid terminal triethoxysilylpropyl derivative.

CF₃CF₂CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂CH₂CH₂CH₂Si(OCH₂CH₃)₃

¹H-NMR (CDCl₃, 300.4 Hz):

-   -   δ3.83:—Si(OCH₂ CH₃)₃(q)    -   2.92:—CF₂CH₂ CF₂-(quin)    -   2.13:—CH₂ CH₂CH₂-(tt)    -   1.75:—CH₂CH₂ CH₂-(m)    -   1.21:—Si(OCH₂CH₃ )₃(t)    -   0.70:—CH₂CH₂CH ₂-(t)

¹⁹F-NMR (CDCl₃, 282.65 Hz):

-   -   −82.2:CF₃ CF₂CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂CH₂—    -   −113.2:CF₃CF₂CF₂CF₂ CH₂CF₂ CF₂CF₂CF₂CF₂CH₂—    -   −115.6:CF₃CF₂CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂ CH₂—    -   −122.5:CF₃CF₂CF₂CF₂CH₂CF₂CF₂ CF₂CF₂CF₂CH₂—    -   −124.0 to −126.0:CF₃CF₂CF₂ CF₂CH₂CF₂CF₂CF₂ CF₂ CF₂CH₂—    -   −127.0:CF₃CF₂ CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂CH₂—

Reference Example 2

A 100-ml three-necked flask was equipped with a septum and a Dimrothcondenser in the presence of inert nitrogen gas. 20.0 g (0.04 mol) ofthe terminal allyl compound obtained in Example 2 and 4.8 ml (0.05 mmol)of trichlorosilane SiHCl₃ were placed in the three-necked flask. Thecontent of the three-necked flask was stirred, and the temperature wasincreased to 40° C. After the temperature increase, 14.5 mg (0.1 mol %based on the terminal allyl compound) of Karstedt's catalyst(Pt.CH₂═CHSiMe₂OMe₂SiCH═CH₂) was added to initiate the reaction. The oilbath temperature was gradually increased. When the temperature reached100° C., the temperature was maintained at a constant, and stirring wasperformed for the whole day and night. After the disappearance of rawmaterials was confirmed by NMR, the reaction was stopped by cooling thereaction mixture to room temperature.

Next, without purifying a terminal trichlorosilyl product produced bythis reaction, 3.7 ml (0.05 mol) of methyl orthoformate CH(OCH₃)₃ wasadded thereto, and the mixture was heated to 40° C. After confirmingthat the reaction solution became homogeneous, 5.6 ml (0.15 mol) ofmethanol was added, and the mixture was stirred for 1 hour, followed bydistilling off of low-boiling components and vacuum distillation,thereby obtaining 10.10 g (yield: 41%) of the target compound, i.e., atransparent liquid terminal trimethoxysilylpropyl derivative.

CF₃CF₂CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂CH₂CH₂CH₂Si(OCH₃)₃

¹H-NMR (CDCl₃, 300.4 Hz):

-   -   δ3.58:—Si(OCH ₃)₃(s)    -   2.92:—CF₂CH₂ CF₂-(quin)    -   2.12:—CH₂ CH₂CH₂-(tt)    -   1.74:—CH₂CH₂ CH₂-(m)    -   0.72:—CH₂CH₂CH₂ -(t)

¹⁹F-NMR (CDCl₃, 282.65 Hz):

-   -   −82.1:CF₃ CF₂CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂CH₂—    -   −113.2:CF₃CF₂CF₂CF₂ CH₂CF₂ CF₂CF₂CF₂CF₂CH₂—    -   −115.6:CF₃CF₂CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂ CH₂—    -   −122.5:CF₃CF₂CF₂CF₂CH₂CF₂CF₂ CF₂CF₂CF₂CH₂—    -   −124.0 to −126.0:CF₃CF₂CF₂ CF₂CH₂CF₂CF₂CF₂ CF₂ CF₂CH₂—    -   −127.0:CF₃CF₂ CF₂CF₂CH₂CF₂CF₂CF₂CF₂CF₂CH₂—

Comparative Example

In Reference Example 2, 30 g (0.08 mol) of C₆F₁₃CH₂CH═CH₂ was used inplace of the terminal allyl compound, and the amount of the Karstedt'scatalyst was changed to 31.6 g (0.1 mol % based on the terminal allylcompound), the amount of trichlorosilane was changed to 10.1 ml (0.105mol), the amount of methanol was changed to 12 ml (0.30 mol), the amountof methyl orthoformate was changed to 7.7 ml (0.1 mol), and thetemperature to react with trichlorosilane was changed to 60° C.,respectively. As a result, 31.66 g (yield: 79%) of a transparent liquidterminal trimethoxysilylpropyl derivative was obtained.

CF₃CF₂CF₂CF₂CF₂CF₂CH₂CH₂CH₂—Si(OCH₃)₃

¹H-NMR (CDCl₃, 300.4 Hz):

-   -   δ3.63:—Si(OCH₃ )₃(s)    -   2.10:—CH₂ CH₂CH₂-(quin)    -   1.81:—CH₂CH₂ CH₂-(m)    -   1.74:—CH₂CH₂CH₂ -(t)

¹⁹F-NMR (CDCl₃, 282.65 Hz):

-   -   −82.0:CF₃ CF₂CF₂CF₂CF₂CF₂CH₂—    -   −115.6:CF₃CF₂CF₂CF₂CF₂CF₂ CH₂—    -   −123.1:CF₃CF₂CF₂CF₂CF₂ CF₂CH₂—    -   −124.0:CF₃CF₂CF₂ CF₂CF₂CF₂CH₂—    -   −124.8:CF₃CF₂CF₂CF₂ CF₂CF₂CH₂—    -   −127.3:CF₃CF₂ CF₂CF₂CF₂CF₂CH₂—

Reference Example 3

-   -   Substrate: Matsunami Glass (Preclean water edge polishing 57213)    -   Solution: 100 g of Vertrel, 0.1 g of sample, 40 mg of 0.05 M        hydrochloric acid, and 5 ml of methanol    -   Coating conditions: spin coating, 0.5 g, 1000 rpm, 30 seconds    -   Drying conditions: 23° C., 50% RH

The following table shows the results of the measurement of the contactangle of each sample under the above conditions.

TABLE Contact angle (°) No. Sample H₂O Hexadecane 1 Ref. Ex. 1 108 69 2Ref. Ex. 2 108 69 3 C₆F₁₃CH₂CH₂Si(OEt)₃ 106 63 4 Comp. Ex. 106 73 5C₈F₁₇CH₂CH₂Si(OEt)₃ 109 69

The invention claimed is:
 1. A carboxylic acid allyl adduct of thegeneral formula:CF₃(CF₂)_(n)(CH₂CF₂)_(a)(CF₂CF₂)_(b)CH₂CHICH₂OCOR′  [II] wherein n is aninteger of 0 to 5, a is 1 or 2, and b is an integer of 0 to 3, and R′ isa C₁-C₃ alkyl group.
 2. A method for producing the carboxylic acid allyladduct according to claim 1, the method comprising reactingpolyfluoroalkyl iodide represented by the general formula:CF₃(CF₂)_(n)(CH₂CF₂)_(a)(CF₂CF₂)_(b)I  [III] wherein n is an integer of0 to 5, a is 1 or 2, and b is an integer of 0 to 3, with carboxylic acidallyl R′COOCH₂CH═CH₂ wherein R′ is a C1-C3 alkyl group.